Analysis of laryngeal movement by digital subtraction laryngography

Fine movement of laryngeal components was analyzed by digital subtraction laryngography with the use of a digital fluorography system. Two kinds of image processing modes, the super pulse image subtraction mode and the time interval difference mode, were used for this purpose. By the super pulse image mode, the distance and extent of movement of laryngeal components at vocal initiation and during phonation could be observed. By the time interval difference mode, the amount and direction of motion for a certain interval and fine movement, such as vocal initiation, were determined.